/*****************************************************************************
* ppp_oe.c - PPP Over Ethernet implementation for lwIP.
*
* Copyright (c) 2006 by Marc Boucher, Services Informatiques (MBSI) inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 06-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
*****************************************************************************/



/* based on NetBSD: if_pppoe.c,v 1.64 2006/01/31 23:50:15 martin Exp */

/*-
 * Copyright (c) 2002 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Martin Husemann <martin@NetBSD.org>.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "lwip/opt.h"

#if PPPOE_SUPPORT /* don't build if not configured for use in lwipopts.h */

#include "ppp.h"
#include "pppdebug.h"

#include "lwip/sys.h"

#include "netif/ppp_oe.h"
#include "netif/etharp.h"

#include <string.h>
#include <stdio.h>

/** @todo Replace this part with a simple list like other lwIP lists */
#ifndef _SYS_QUEUE_H_
#define _SYS_QUEUE_H_

/*
 * A list is headed by a single forward pointer (or an array of forward
 * pointers for a hash table header). The elements are doubly linked
 * so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before
 * or after an existing element or at the head of the list. A list
 * may only be traversed in the forward direction.
 *
 * For details on the use of these macros, see the queue(3) manual page.
 */

/*
 * List declarations.
 */
#define  LIST_HEAD(name, type)                                                 \
    struct name {                                                                  \
        struct type *lh_first; /* first element */                                  \
    }

#define  LIST_HEAD_INITIALIZER(head)                                           \
    { NULL }

#define  LIST_ENTRY(type)                                                      \
    struct {                                                                       \
        struct type *le_next;  /* next element */                                    \
        struct type **le_prev; /* address of previous next element */                \
    }

/*
 * List functions.
 */

#define  LIST_EMPTY(head)  ((head)->lh_first == NULL)

#define  LIST_FIRST(head)  ((head)->lh_first)

#define  LIST_FOREACH(var, head, field)                                        \
    for ((var) = LIST_FIRST((head));                                             \
         (var);                                                                   \
         (var) = LIST_NEXT((var), field))

#define  LIST_INIT(head) do {                                                  \
        LIST_FIRST((head)) = NULL;                                                   \
} while (0)

#define  LIST_INSERT_AFTER(listelm, elm, field) do {                           \
        if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL) {         \
            LIST_NEXT((listelm), field)->field.le_prev =                               \
                &LIST_NEXT((elm), field); }                                              \
        LIST_NEXT((listelm), field) = (elm);                                         \
        (elm)->field.le_prev = &LIST_NEXT((listelm), field);                         \
} while (0)

#define  LIST_INSERT_BEFORE(listelm, elm, field) do {                          \
        (elm)->field.le_prev = (listelm)->field.le_prev;                             \
        LIST_NEXT((elm), field) = (listelm);                                         \
        *(listelm)->field.le_prev = (elm);                                           \
        (listelm)->field.le_prev = &LIST_NEXT((elm), field);                         \
} while (0)

#define  LIST_INSERT_HEAD(head, elm, field) do {                               \
        if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) {                  \
            LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field); }              \
        LIST_FIRST((head)) = (elm);                                                  \
        (elm)->field.le_prev = &LIST_FIRST((head));                                  \
} while (0)

#define  LIST_NEXT(elm, field)  ((elm)->field.le_next)

#define  LIST_REMOVE(elm, field) do {                                          \
        if (LIST_NEXT((elm), field) != NULL) {                                         \
            LIST_NEXT((elm), field)->field.le_prev =                                   \
                (elm)->field.le_prev; }                                                  \
        *(elm)->field.le_prev = LIST_NEXT((elm), field);                             \
} while (0)

#endif /* !_SYS_QUEUE_H_ */


/* Add a 16 bit unsigned value to a buffer pointed to by PTR */
#define PPPOE_ADD_16(PTR, VAL) \
    *(PTR)++ = (VAL) / 256;    \
    *(PTR)++ = (VAL) % 256

/* Add a complete PPPoE header to the buffer pointed to by PTR */
#define PPPOE_ADD_HEADER(PTR, CODE, SESS, LEN)  \
    *(PTR)++ = PPPOE_VERTYPE;  \
    *(PTR)++ = (CODE);         \
    PPPOE_ADD_16(PTR, SESS);   \
    PPPOE_ADD_16(PTR, LEN)

#define PPPOE_DISC_TIMEOUT (5 * 1000)  /* base for quick timeout calculation */
#define PPPOE_SLOW_RETRY   (60 * 1000) /* persistent retry interval */
#define PPPOE_DISC_MAXPADI  4          /* retry PADI four times (quickly) */
#define PPPOE_DISC_MAXPADR  2          /* retry PADR twice */

#ifdef PPPOE_SERVER
/* from if_spppsubr.c */
#define IFF_PASSIVE IFF_LINK0 /* wait passively for connection */
#endif

struct pppoe_softc
{
    LIST_ENTRY(pppoe_softc) sc_list;
    struct netif *sc_ethif;    /* ethernet interface we are using */
    int sc_pd;                 /* ppp unit number */
    void (*sc_linkStatusCB)(int pd, int up);

    int sc_state;               /* discovery phase or session connected */
    struct eth_addr sc_dest;    /* hardware address of concentrator */
    u16_t sc_session;           /* PPPoE session id */

    char *sc_service_name;      /* if != NULL: requested name of service */
    char *sc_concentrator_name; /* if != NULL: requested concentrator id */
    u8_t *sc_ac_cookie;         /* content of AC cookie we must echo back */
    size_t sc_ac_cookie_len;    /* length of cookie data */
#ifdef PPPOE_SERVER
    u8_t *sc_hunique;           /* content of host unique we must echo back */
    size_t sc_hunique_len;      /* length of host unique */
#endif
    int sc_padi_retried;        /* number of PADI retries already done */
    int sc_padr_retried;        /* number of PADR retries already done */
};

/* input routines */
static void pppoe_dispatch_disc_pkt(struct netif *, struct pbuf *);

/* management routines */
static int pppoe_do_disconnect(struct pppoe_softc *);
static void pppoe_abort_connect(struct pppoe_softc *);
static void pppoe_clear_softc(struct pppoe_softc *, const char *);

/* internal timeout handling */
static void pppoe_timeout(void *);

/* sending actual protocol controll packets */
static err_t pppoe_send_padi(struct pppoe_softc *);
static err_t pppoe_send_padr(struct pppoe_softc *);
#ifdef PPPOE_SERVER
static err_t pppoe_send_pado(struct pppoe_softc *);
static err_t pppoe_send_pads(struct pppoe_softc *);
#endif
static err_t pppoe_send_padt(struct netif *, u_int, const u8_t *);

/* internal helper functions */
static struct pppoe_softc * pppoe_find_softc_by_session(u_int, struct netif *);
static struct pppoe_softc * pppoe_find_softc_by_hunique(u8_t *, size_t, struct netif *);

static LIST_HEAD(pppoe_softc_head, pppoe_softc) pppoe_softc_list;

int pppoe_hdrlen;

void
pppoe_init(void)
{
    pppoe_hdrlen = sizeof(struct eth_hdr) + PPPOE_HEADERLEN;
    LIST_INIT(&pppoe_softc_list);
}

err_t
pppoe_create(struct netif *ethif, int pd, void (*linkStatusCB)(int pd, int up), struct pppoe_softc **scptr)
{
    struct pppoe_softc *sc;

    sc = mem_malloc(sizeof(struct pppoe_softc));
    if (!sc)
    {
        *scptr = NULL;
        return ERR_MEM;
    }
    memset(sc, 0, sizeof(struct pppoe_softc));

    /* changed to real address later */
    MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));

    sc->sc_pd = pd;
    sc->sc_linkStatusCB = linkStatusCB;
    sc->sc_ethif = ethif;

    LIST_INSERT_HEAD(&pppoe_softc_list, sc, sc_list);

    *scptr = sc;

    return ERR_OK;
}

err_t
pppoe_destroy(struct netif *ifp)
{
    struct pppoe_softc * sc;

    LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
        if (sc->sc_ethif == ifp)
        {
            break;
        }
    }

    if (!(sc && (sc->sc_ethif == ifp)))
    {
        return ERR_IF;
    }

    tcpip_untimeout(pppoe_timeout, sc);
    LIST_REMOVE(sc, sc_list);

    if (sc->sc_concentrator_name)
    {
        mem_free(sc->sc_concentrator_name);
    }
    if (sc->sc_service_name)
    {
        mem_free(sc->sc_service_name);
    }
    if (sc->sc_ac_cookie)
    {
        mem_free(sc->sc_ac_cookie);
    }
    mem_free(sc);

    return ERR_OK;
}

/*
 * Find the interface handling the specified session.
 * Note: O(number of sessions open), this is a client-side only, mean
 * and lean implementation, so number of open sessions typically should
 * be 1.
 */
static struct pppoe_softc *
pppoe_find_softc_by_session(u_int session, struct netif *rcvif)
{
    struct pppoe_softc *sc;

    if (session == 0)
    {
        return NULL;
    }

    LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
        if (sc->sc_state == PPPOE_STATE_SESSION
            && sc->sc_session == session)
        {
            if (sc->sc_ethif == rcvif)
            {
                return sc;
            }
            else
            {
                return NULL;
            }
        }
    }
    return NULL;
}

/* Check host unique token passed and return appropriate softc pointer,
 * or NULL if token is bogus. */
static struct pppoe_softc *
pppoe_find_softc_by_hunique(u8_t *token, size_t len, struct netif *rcvif)
{
    struct pppoe_softc *sc, *t;

    if (LIST_EMPTY(&pppoe_softc_list))
    {
        return NULL;
    }

    if (len != sizeof sc)
    {
        return NULL;
    }
    MEMCPY(&t, token, len);

    LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
        if (sc == t)
        {
            break;
        }
    }

    if (sc == NULL)
    {
        PPPDEBUG((LOG_DEBUG, "pppoe: alien host unique tag, no session found\n"));
        return NULL;
    }

    /* should be safe to access *sc now */
    if (sc->sc_state < PPPOE_STATE_PADI_SENT || sc->sc_state >= PPPOE_STATE_SESSION)
    {
        printf("%c%c%"U 16_F ": host unique tag found, but it belongs to a connection in state %d\n",
               sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, sc->sc_state);
        return NULL;
    }
    if (sc->sc_ethif != rcvif)
    {
        printf("%c%c%"U 16_F ": wrong interface, not accepting host unique\n",
               sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
        return NULL;
    }
    return sc;
}

static void
pppoe_linkstatus_up(void *arg)
{
    struct pppoe_softc *sc = (struct pppoe_softc*)arg;

    sc->sc_linkStatusCB(sc->sc_pd, 1);
}

/* analyze and handle a single received packet while not in session state */
static void
pppoe_dispatch_disc_pkt(struct netif *netif, struct pbuf *pb)
{
    u16_t tag, len;
    u16_t session, plen;
    struct pppoe_softc *sc;
    const char *err_msg;
    char devname[6];
    char *error;
    u8_t *ac_cookie;
    size_t ac_cookie_len;

#ifdef PPPOE_SERVER
    u8_t *hunique;
    size_t hunique_len;
#endif
    struct pppoehdr *ph;
    struct pppoetag pt;
    int off, err, errortag;
    struct eth_hdr *ethhdr;

    pb = pppSingleBuf(pb);

    strcpy(devname, "pppoe"); /* as long as we don't know which instance */
    err_msg = NULL;
    errortag = 0;
    if (pb->len < sizeof(*ethhdr))
    {
        goto done;
    }
    ethhdr = (struct eth_hdr*)pb->payload;
    off = sizeof(*ethhdr);

    ac_cookie = NULL;
    ac_cookie_len = 0;
#ifdef PPPOE_SERVER
    hunique = NULL;
    hunique_len = 0;
#endif
    session = 0;
    if (pb->len - off < PPPOE_HEADERLEN)
    {
        printf("pppoe: packet too short: %d\n", pb->len);
        goto done;
    }

    ph = (struct pppoehdr*)(ethhdr + 1);
    if (ph->vertype != PPPOE_VERTYPE)
    {
        printf("pppoe: unknown version/type packet: 0x%x\n", ph->vertype);
        goto done;
    }
    session = ntohs(ph->session);
    plen = ntohs(ph->plen);
    off += sizeof(*ph);

    if (plen + off > pb->len)
    {
        printf("pppoe: packet content does not fit: data available = %d, packet size = %u\n",
               pb->len - off, plen);
        goto done;
    }
    if (pb->tot_len == pb->len)
    {
        pb->tot_len = pb->len = off + plen; /* ignore trailing garbage */
    }
    tag = 0;
    len = 0;
    sc = NULL;
    while (off + sizeof(pt) <= pb->len)
    {
        MEMCPY(&pt, (u8_t*)pb->payload + off, sizeof(pt));
        tag = ntohs(pt.tag);
        len = ntohs(pt.len);
        if (off + sizeof(pt) + len > pb->len)
        {
            printf("pppoe: tag 0x%x len 0x%x is too long\n", tag, len);
            goto done;
        }
        switch (tag)
        {
        case PPPOE_TAG_EOL:
            goto breakbreak;
        case PPPOE_TAG_SNAME:
            break; /* ignored */
        case PPPOE_TAG_ACNAME:
            break; /* ignored */
        case PPPOE_TAG_HUNIQUE:
            if (sc != NULL)
            {
                break;
            }
#ifdef PPPOE_SERVER
            hunique = (u8_t*)pb->payload + off + sizeof(pt);
            hunique_len = len;
#endif
            sc = pppoe_find_softc_by_hunique((u8_t*)pb->payload + off + sizeof(pt), len, netif);
            if (sc != NULL)
            {
                snprintf(devname, sizeof(devname), "%c%c%"U 16_F, sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
            }
            break;
        case PPPOE_TAG_ACCOOKIE:
            if (ac_cookie == NULL)
            {
                ac_cookie = (u8_t*)pb->payload + off + sizeof(pt);
                ac_cookie_len = len;
            }
            break;
        case PPPOE_TAG_SNAME_ERR:
            err_msg = "SERVICE NAME ERROR";
            errortag = 1;
            break;
        case PPPOE_TAG_ACSYS_ERR:
            err_msg = "AC SYSTEM ERROR";
            errortag = 1;
            break;
        case PPPOE_TAG_GENERIC_ERR:
            err_msg = "GENERIC ERROR";
            errortag = 1;
            break;
        }
        if (err_msg)
        {
            error = NULL;
            if (errortag && len)
            {
                error = mem_malloc(len + 1);
                if (error)
                {
                    strncpy(error, (char*)pb->payload + off + sizeof(pt), len);
                    error[len - 1] = '\0';
                }
            }
            if (error)
            {
                printf("%s: %s: %s\n", devname, err_msg, error);
                mem_free(error);
            }
            else
            {
                printf("%s: %s\n", devname, err_msg);
            }
            if (errortag)
            {
                goto done;
            }
        }
        off += sizeof(pt) + len;
    }

breakbreak:;
    switch (ph->code)
    {
    case PPPOE_CODE_PADI:
#ifdef PPPOE_SERVER
        /*
         * got service name, concentrator name, and/or host unique.
         * ignore if we have no interfaces with IFF_PASSIVE|IFF_UP.
         */
        if (LIST_EMPTY(&pppoe_softc_list))
        {
            goto done;
        }
        LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
            if (!(sc->sc_sppp.pp_if.if_flags & IFF_UP))
            {
                continue;
            }
            if (!(sc->sc_sppp.pp_if.if_flags & IFF_PASSIVE))
            {
                continue;
            }
            if (sc->sc_state == PPPOE_STATE_INITIAL)
            {
                break;
            }
        }
        if (sc == NULL)
        {
            /* printf("pppoe: free passive interface is not found\n"); */
            goto done;
        }
        if (hunique)
        {
            if (sc->sc_hunique)
            {
                mem_free(sc->sc_hunique);
            }
            sc->sc_hunique = mem_malloc(hunique_len);
            if (sc->sc_hunique == NULL)
            {
                goto done;
            }
            sc->sc_hunique_len = hunique_len;
            MEMCPY(sc->sc_hunique, hunique, hunique_len);
        }
        MEMCPY(&sc->sc_dest, eh->ether_shost, sizeof sc->sc_dest);
        sc->sc_state = PPPOE_STATE_PADO_SENT;
        pppoe_send_pado(sc);
        break;
  #endif /* PPPOE_SERVER */
    case PPPOE_CODE_PADR:
  #ifdef PPPOE_SERVER
        /*
         * get sc from ac_cookie if IFF_PASSIVE
         */
        if (ac_cookie == NULL)
        {
            /* be quiet if there is not a single pppoe instance */
            printf("pppoe: received PADR but not includes ac_cookie\n");
            goto done;
        }
        sc = pppoe_find_softc_by_hunique(ac_cookie, ac_cookie_len, netif);
        if (sc == NULL)
        {
            /* be quiet if there is not a single pppoe instance */
            if (!LIST_EMPTY(&pppoe_softc_list))
            {
                printf("pppoe: received PADR but could not find request for it\n");
            }
            goto done;
        }
        if (sc->sc_state != PPPOE_STATE_PADO_SENT)
        {
            printf("%c%c%"U 16_F ": received unexpected PADR\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
            goto done;
        }
        if (hunique)
        {
            if (sc->sc_hunique)
            {
                mem_free(sc->sc_hunique);
            }
            sc->sc_hunique = mem_malloc(hunique_len);
            if (sc->sc_hunique == NULL)
            {
                goto done;
            }
            sc->sc_hunique_len = hunique_len;
            MEMCPY(sc->sc_hunique, hunique, hunique_len);
        }
        pppoe_send_pads(sc);
        sc->sc_state = PPPOE_STATE_SESSION;
        tcpip_timeout(100, pppoe_linkstatus_up, sc); /* notify upper layers */
        break;
  #else
        /* ignore, we are no access concentrator */
        goto done;
  #endif /* PPPOE_SERVER */
    case PPPOE_CODE_PADO:
        if (sc == NULL)
        {
            /* be quiet if there is not a single pppoe instance */
            if (!LIST_EMPTY(&pppoe_softc_list))
            {
                printf("pppoe: received PADO but could not find request for it\n");
            }
            goto done;
        }
        if (sc->sc_state != PPPOE_STATE_PADI_SENT)
        {
            printf("%c%c%"U 16_F ": received unexpected PADO\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
            goto done;
        }
        if (ac_cookie)
        {
            if (sc->sc_ac_cookie)
            {
                mem_free(sc->sc_ac_cookie);
            }
            sc->sc_ac_cookie = mem_malloc(ac_cookie_len);
            if (sc->sc_ac_cookie == NULL)
            {
                goto done;
            }
            sc->sc_ac_cookie_len = ac_cookie_len;
            MEMCPY(sc->sc_ac_cookie, ac_cookie, ac_cookie_len);
        }
        MEMCPY(&sc->sc_dest, ethhdr->src.addr, sizeof(sc->sc_dest.addr));
        tcpip_untimeout(pppoe_timeout, sc);
        sc->sc_padr_retried = 0;
        sc->sc_state = PPPOE_STATE_PADR_SENT;
        if ((err = pppoe_send_padr(sc)) != 0)
        {
            PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": failed to send PADR, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
        }
        tcpip_timeout(PPPOE_DISC_TIMEOUT * (1 + sc->sc_padr_retried), pppoe_timeout, sc);
        break;
    case PPPOE_CODE_PADS:
        if (sc == NULL)
        {
            goto done;
        }
        sc->sc_session = session;
        tcpip_untimeout(pppoe_timeout, sc);
        PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": session 0x%x connected\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, session));
        sc->sc_state = PPPOE_STATE_SESSION;
        tcpip_timeout(100, pppoe_linkstatus_up, sc); /* notify upper layers */
        break;
    case PPPOE_CODE_PADT:
        if (sc == NULL)
        {
            goto done;
        }
        pppoe_clear_softc(sc, "received PADT");
        break;
    default:
        if (sc)
        {
            printf("%c%c%"U 16_F ": unknown code (0x%04x) session = 0x%04x\n",
                   sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num,
                   ph->code, session);
        }
        else
        {
            printf("pppoe: unknown code (0x%04x) session = 0x%04x\n", ph->code, session);
        }
        break;
    }

done:
    pbuf_free(pb);
    return;
}

void
pppoe_disc_input(struct netif *netif, struct pbuf *p)
{
    /* avoid error messages if there is not a single pppoe instance */
    if (!LIST_EMPTY(&pppoe_softc_list))
    {
        pppoe_dispatch_disc_pkt(netif, p);
    }
    else
    {
        pbuf_free(p);
    }
}

void
pppoe_data_input(struct netif *netif, struct pbuf *pb)
{
    u16_t session, plen;
    struct pppoe_softc *sc;
    struct pppoehdr *ph;

#ifdef PPPOE_TERM_UNKNOWN_SESSIONS
    u8_t shost[ETHER_ADDR_LEN];
#endif

#ifdef PPPOE_TERM_UNKNOWN_SESSIONS
    MEMCPY(shost, ((struct eth_hdr*)pb->payload)->src.addr, sizeof(shost));
#endif
    if (pbuf_header(pb, -(int)sizeof(struct eth_hdr)) != 0)
    {
        /* bail out */
        PPPDEBUG((LOG_ERR, "pppoe_data_input: pbuf_header failed\n"));
        LINK_STATS_INC(link.lenerr);
        goto drop;
    }

    pb = pppSingleBuf(pb);

    if (pb->len <= PPPOE_HEADERLEN)
    {
        printf("pppoe (data): dropping too short packet: %d bytes\n", pb->len);
        goto drop;
    }

    if (pb->len < sizeof(*ph))
    {
        printf("pppoe_data_input: could not get PPPoE header\n");
        goto drop;
    }
    ph = (struct pppoehdr*)pb->payload;

    if (ph->vertype != PPPOE_VERTYPE)
    {
        printf("pppoe (data): unknown version/type packet: 0x%x\n", ph->vertype);
        goto drop;
    }
    if (ph->code != 0)
    {
        goto drop;
    }

    session = ntohs(ph->session);
    sc = pppoe_find_softc_by_session(session, netif);
    if (sc == NULL)
    {
#ifdef PPPOE_TERM_UNKNOWN_SESSIONS
        printf("pppoe: input for unknown session 0x%x, sending PADT\n", session);
        pppoe_send_padt(netif, session, shost);
#endif
        goto drop;
    }

    plen = ntohs(ph->plen);

    if (pbuf_header(pb, -(int)(PPPOE_HEADERLEN)) != 0)
    {
        /* bail out */
        PPPDEBUG((LOG_ERR, "pppoe_data_input: pbuf_header PPPOE_HEADERLEN failed\n"));
        LINK_STATS_INC(link.lenerr);
        goto drop;
    }

    PPPDEBUG((LOG_DEBUG, "pppoe_data_input: %c%c%"U 16_F ": pkthdr.len=%d, pppoe.len=%d\n",
              sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num,
              pb->len, plen));

    if (pb->len < plen)
    {
        goto drop;
    }

    pppInProcOverEthernet(sc->sc_pd, pb);

    return;

drop:
    pbuf_free(pb);
}

static err_t
pppoe_output(struct pppoe_softc *sc, struct pbuf *pb)
{
    struct eth_hdr *ethhdr;
    u16_t etype;
    err_t res;

    if (!sc->sc_ethif)
    {
        pbuf_free(pb);
        return ERR_IF;
    }

    ethhdr = (struct eth_hdr*)pb->payload;
    etype = sc->sc_state == PPPOE_STATE_SESSION ? ETHTYPE_PPPOE : ETHTYPE_PPPOEDISC;
    ethhdr->type = htons(etype);
    MEMCPY(ethhdr->dest.addr, sc->sc_dest.addr, sizeof(ethhdr->dest.addr));
    MEMCPY(ethhdr->src.addr, ((struct eth_addr*)sc->sc_ethif->hwaddr)->addr, sizeof(ethhdr->src.addr));

    PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F " (%x) state=%d, session=0x%x output -> %02"X 16_F ":%02"X 16_F ":%02"X 16_F ":%02"X 16_F ":%02"X 16_F ":%02"X 16_F ", len=%d\n",
              sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, etype,
              sc->sc_state, sc->sc_session,
              sc->sc_dest.addr[0], sc->sc_dest.addr[1], sc->sc_dest.addr[2], sc->sc_dest.addr[3], sc->sc_dest.addr[4], sc->sc_dest.addr[5],
              pb->tot_len));

    res = sc->sc_ethif->linkoutput(sc->sc_ethif, pb);

    pbuf_free(pb);

    return res;
}

static err_t
pppoe_send_padi(struct pppoe_softc *sc)
{
    struct pbuf *pb;
    u8_t *p;
    int len, l1 = 0, l2 = 0; /* XXX: gcc */

    if (sc->sc_state > PPPOE_STATE_PADI_SENT)
    {
        PPPDEBUG((LOG_ERR, "ERROR: pppoe_send_padi in state %d", sc->sc_state));
    }

    /* calculate length of frame (excluding ethernet header + pppoe header) */
    len = 2 + 2 + 2 + 2 + sizeof sc; /* service name tag is required, host unique is send too */
    if (sc->sc_service_name != NULL)
    {
        l1 = strlen(sc->sc_service_name);
        len += l1;
    }
    if (sc->sc_concentrator_name != NULL)
    {
        l2 = strlen(sc->sc_concentrator_name);
        len += 2 + 2 + l2;
    }

    /* allocate a buffer */
    pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len, PBUF_RAM);
    if (!pb)
    {
        return ERR_MEM;
    }

    p = (u8_t*)pb->payload + sizeof(struct eth_hdr);
    /* fill in pkt */
    PPPOE_ADD_HEADER(p, PPPOE_CODE_PADI, 0, len);
    PPPOE_ADD_16(p, PPPOE_TAG_SNAME);
    if (sc->sc_service_name != NULL)
    {
        PPPOE_ADD_16(p, l1);
        MEMCPY(p, sc->sc_service_name, l1);
        p += l1;
    }
    else
    {
        PPPOE_ADD_16(p, 0);
    }
    if (sc->sc_concentrator_name != NULL)
    {
        PPPOE_ADD_16(p, PPPOE_TAG_ACNAME);
        PPPOE_ADD_16(p, l2);
        MEMCPY(p, sc->sc_concentrator_name, l2);
        p += l2;
    }
    PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
    PPPOE_ADD_16(p, sizeof(sc));
    MEMCPY(p, &sc, sizeof sc);

    /* send pkt */
    return pppoe_output(sc, pb);
}

static void
pppoe_timeout(void *arg)
{
    int retry_wait, err;
    struct pppoe_softc *sc = (struct pppoe_softc*)arg;

    PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": timeout\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num));

    switch (sc->sc_state)
    {
    case PPPOE_STATE_PADI_SENT:
        /*
         * We have two basic ways of retrying:
         *  - Quick retry mode: try a few times in short sequence
         *  - Slow retry mode: we already had a connection successfully
         *    established and will try infinitely (without user
         *    intervention)
         * We only enter slow retry mode if IFF_LINK1 (aka autodial)
         * is not set.
         */

        /* initialize for quick retry mode */
        retry_wait = PPPOE_DISC_TIMEOUT * (1 + sc->sc_padi_retried);

        sc->sc_padi_retried++;
        if (sc->sc_padi_retried >= PPPOE_DISC_MAXPADI)
        {
#if 0
            if ((sc->sc_sppp.pp_if.if_flags & IFF_LINK1) == 0)
            {
                /* slow retry mode */
                retry_wait = PPPOE_SLOW_RETRY;
            }
            else
#endif
            {
                pppoe_abort_connect(sc);
                return;
            }
        }
        if ((err = pppoe_send_padi(sc)) != 0)
        {
            sc->sc_padi_retried--;
            PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": failed to transmit PADI, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
        }
        tcpip_timeout(retry_wait, pppoe_timeout, sc);
        break;

    case PPPOE_STATE_PADR_SENT:
        sc->sc_padr_retried++;
        if (sc->sc_padr_retried >= PPPOE_DISC_MAXPADR)
        {
            MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
            sc->sc_state = PPPOE_STATE_PADI_SENT;
            sc->sc_padr_retried = 0;
            if ((err = pppoe_send_padi(sc)) != 0)
            {
                PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": failed to send PADI, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
            }
            tcpip_timeout(PPPOE_DISC_TIMEOUT * (1 + sc->sc_padi_retried), pppoe_timeout, sc);
            return;
        }
        if ((err = pppoe_send_padr(sc)) != 0)
        {
            sc->sc_padr_retried--;
            PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": failed to send PADR, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
        }
        tcpip_timeout(PPPOE_DISC_TIMEOUT * (1 + sc->sc_padr_retried), pppoe_timeout, sc);
        break;
    case PPPOE_STATE_CLOSING:
        pppoe_do_disconnect(sc);
        break;
    default:
        return; /* all done, work in peace */
    }
}

/* Start a connection (i.e. initiate discovery phase) */
int
pppoe_connect(struct pppoe_softc *sc)
{
    int err;

    if (sc->sc_state != PPPOE_STATE_INITIAL)
    {
        return EBUSY;
    }

#ifdef PPPOE_SERVER
    /* wait PADI if IFF_PASSIVE */
    if ((sc->sc_sppp.pp_if.if_flags & IFF_PASSIVE))
    {
        return 0;
    }
#endif
    /* save state, in case we fail to send PADI */
    sc->sc_state = PPPOE_STATE_PADI_SENT;
    sc->sc_padr_retried = 0;
    err = pppoe_send_padi(sc);
    PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": failed to send PADI, error=%d\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, err));
    tcpip_timeout(PPPOE_DISC_TIMEOUT, pppoe_timeout, sc);
    return err;
}

/* disconnect */
void
pppoe_disconnect(struct pppoe_softc *sc)
{
    if (sc->sc_state < PPPOE_STATE_SESSION)
    {
        return;
    }
    /*
     * Do not call pppoe_disconnect here, the upper layer state
     * machine gets confused by this. We must return from this
     * function and defer disconnecting to the timeout handler.
     */
    sc->sc_state = PPPOE_STATE_CLOSING;
    tcpip_timeout(20, pppoe_timeout, sc);
}

static int
pppoe_do_disconnect(struct pppoe_softc *sc)
{
    int err;

    if (sc->sc_state < PPPOE_STATE_SESSION)
    {
        err = EBUSY;
    }
    else
    {
        PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": disconnecting\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num));
        err = pppoe_send_padt(sc->sc_ethif, sc->sc_session, (const u8_t*)&sc->sc_dest);
    }

    /* cleanup softc */
    sc->sc_state = PPPOE_STATE_INITIAL;
    MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
    if (sc->sc_ac_cookie)
    {
        mem_free(sc->sc_ac_cookie);
        sc->sc_ac_cookie = NULL;
    }
    sc->sc_ac_cookie_len = 0;
#ifdef PPPOE_SERVER
    if (sc->sc_hunique)
    {
        mem_free(sc->sc_hunique);
        sc->sc_hunique = NULL;
    }
    sc->sc_hunique_len = 0;
#endif
    sc->sc_session = 0;

    sc->sc_linkStatusCB(sc->sc_pd, 0); /* notify upper layers */

    return err;
}

/* Connection attempt aborted */
static void
pppoe_abort_connect(struct pppoe_softc *sc)
{
    printf("%c%c%"U 16_F ": could not establish connection\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
    sc->sc_state = PPPOE_STATE_CLOSING;

    sc->sc_linkStatusCB(sc->sc_pd, 0); /* notify upper layers */

    /* clear connection state */
    MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
    sc->sc_state = PPPOE_STATE_INITIAL;
}

/* Send a PADR packet */
static err_t
pppoe_send_padr(struct pppoe_softc *sc)
{
    struct pbuf *pb;
    u8_t *p;
    size_t len, l1 = 0; /* XXX: gcc */

    if (sc->sc_state != PPPOE_STATE_PADR_SENT)
    {
        return ERR_CONN;
    }

    len = 2 + 2 + 2 + 2 + sizeof(sc);  /* service name, host unique */
    if (sc->sc_service_name != NULL)   /* service name tag maybe empty */
    {
        l1 = strlen(sc->sc_service_name);
        len += l1;
    }
    if (sc->sc_ac_cookie_len > 0)
    {
        len += 2 + 2 + sc->sc_ac_cookie_len; /* AC cookie */
    }
    pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len, PBUF_RAM);
    if (!pb)
    {
        return ERR_MEM;
    }
    p = (u8_t*)pb->payload + sizeof(struct eth_hdr);
    PPPOE_ADD_HEADER(p, PPPOE_CODE_PADR, 0, len);
    PPPOE_ADD_16(p, PPPOE_TAG_SNAME);
    if (sc->sc_service_name != NULL)
    {
        PPPOE_ADD_16(p, l1);
        MEMCPY(p, sc->sc_service_name, l1);
        p += l1;
    }
    else
    {
        PPPOE_ADD_16(p, 0);
    }
    if (sc->sc_ac_cookie_len > 0)
    {
        PPPOE_ADD_16(p, PPPOE_TAG_ACCOOKIE);
        PPPOE_ADD_16(p, sc->sc_ac_cookie_len);
        MEMCPY(p, sc->sc_ac_cookie, sc->sc_ac_cookie_len);
        p += sc->sc_ac_cookie_len;
    }
    PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
    PPPOE_ADD_16(p, sizeof(sc));
    MEMCPY(p, &sc, sizeof sc);

    return pppoe_output(sc, pb);
}

/* send a PADT packet */
static err_t
pppoe_send_padt(struct netif *outgoing_if, u_int session, const u8_t *dest)
{
    struct pbuf *pb;
    struct eth_hdr *ethhdr;
    err_t res;
    u8_t *p;

    pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN, PBUF_RAM);
    if (!pb)
    {
        return ERR_MEM;
    }

    ethhdr = (struct eth_hdr*)pb->payload;
    ethhdr->type = htons(ETHTYPE_PPPOEDISC);
    MEMCPY(ethhdr->dest.addr, dest, sizeof(ethhdr->dest.addr));
    MEMCPY(ethhdr->src.addr, ((struct eth_addr*)outgoing_if->hwaddr)->addr, sizeof(ethhdr->src.addr));

    p = (u8_t*)(ethhdr + 1);
    PPPOE_ADD_HEADER(p, PPPOE_CODE_PADT, session, 0);

    res = outgoing_if->linkoutput(outgoing_if, pb);

    pbuf_free(pb);

    return res;
}

#ifdef PPPOE_SERVER
static err_t
pppoe_send_pado(struct pppoe_softc *sc)
{
    struct pbuf *pb;
    u8_t *p;
    size_t len;

    if (sc->sc_state != PPPOE_STATE_PADO_SENT)
    {
        return ERR_CONN;
    }

    /* calc length */
    len = 0;
    /* include ac_cookie */
    len += 2 + 2 + sizeof(sc);
    /* include hunique */
    len += 2 + 2 + sc->sc_hunique_len;
    pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len, PBUF_RAM);
    if (!pb)
    {
        return ERR_MEM;
    }
    p = (u8_t*)pb->payload + sizeof(struct eth_hdr);
    PPPOE_ADD_HEADER(p, PPPOE_CODE_PADO, 0, len);
    PPPOE_ADD_16(p, PPPOE_TAG_ACCOOKIE);
    PPPOE_ADD_16(p, sizeof(sc));
    MEMCPY(p, &sc, sizeof(sc));
    p += sizeof(sc);
    PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
    PPPOE_ADD_16(p, sc->sc_hunique_len);
    MEMCPY(p, sc->sc_hunique, sc->sc_hunique_len);
    return pppoe_output(sc, pb);
}

static err_t
pppoe_send_pads(struct pppoe_softc *sc)
{
    struct pbuf *pb;
    u8_t *p;
    size_t len, l1 = 0; /* XXX: gcc */

    if (sc->sc_state != PPPOE_STATE_PADO_SENT)
    {
        return ERR_CONN;
    }

    sc->sc_session = mono_time.tv_sec % 0xff + 1;
    /* calc length */
    len = 0;
    /* include hunique */
    len += 2 + 2 + 2 + 2 + sc->sc_hunique_len; /* service name, host unique*/
    if (sc->sc_service_name != NULL)           /* service name tag maybe empty */
    {
        l1 = strlen(sc->sc_service_name);
        len += l1;
    }
    pb = pbuf_alloc(PBUF_LINK, sizeof(struct eth_hdr) + PPPOE_HEADERLEN + len, PBUF_RAM);
    if (!pb)
    {
        return ERR_MEM;
    }
    p = (u8_t*)pb->payload + sizeof(struct eth_hdr);
    PPPOE_ADD_HEADER(p, PPPOE_CODE_PADS, sc->sc_session, len);
    PPPOE_ADD_16(p, PPPOE_TAG_SNAME);
    if (sc->sc_service_name != NULL)
    {
        PPPOE_ADD_16(p, l1);
        MEMCPY(p, sc->sc_service_name, l1);
        p += l1;
    }
    else
    {
        PPPOE_ADD_16(p, 0);
    }
    PPPOE_ADD_16(p, PPPOE_TAG_HUNIQUE);
    PPPOE_ADD_16(p, sc->sc_hunique_len);
    MEMCPY(p, sc->sc_hunique, sc->sc_hunique_len);
    return pppoe_output(sc, pb);
}
#endif

err_t
pppoe_xmit(struct pppoe_softc *sc, struct pbuf *pb)
{
    u8_t *p;
    size_t len;

    /* are we ready to process data yet? */
    if (sc->sc_state < PPPOE_STATE_SESSION)
    {
        /*sppp_flush(&sc->sc_sppp.pp_if);*/
        pbuf_free(pb);
        return ERR_CONN;
    }

    len = pb->tot_len;

    /* make room for Ethernet header - should not fail */
    if (pbuf_header(pb, sizeof(struct eth_hdr) + PPPOE_HEADERLEN) != 0)
    {
        /* bail out */
        PPPDEBUG((LOG_ERR, "pppoe: %c%c%"U 16_F ": pppoe_xmit: could not allocate room for header\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num));
        LINK_STATS_INC(link.lenerr);
        pbuf_free(pb);
        return ERR_BUF;
    }

    p = (u8_t*)pb->payload + sizeof(struct eth_hdr);
    PPPOE_ADD_HEADER(p, 0, sc->sc_session, len);

    return pppoe_output(sc, pb);
}

#if 0 /*def PFIL_HOOKS*/
static int
pppoe_ifattach_hook(void *arg, struct pbuf **mp, struct netif *ifp, int dir)
{
    struct pppoe_softc *sc;
    int s;

    if (mp != (struct pbuf**)PFIL_IFNET_DETACH)
    {
        return 0;
    }

    LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
        if (sc->sc_ethif != ifp)
        {
            continue;
        }
        if (sc->sc_sppp.pp_if.if_flags & IFF_UP)
        {
            sc->sc_sppp.pp_if.if_flags &= ~(IFF_UP | IFF_RUNNING);
            printf("%c%c%"U 16_F ": ethernet interface detached, going down\n",
                   sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num);
        }
        sc->sc_ethif = NULL;
        pppoe_clear_softc(sc, "ethernet interface detached");
    }

    return 0;
}
#endif

static void
pppoe_clear_softc(struct pppoe_softc *sc, const char *message)
{
    LWIP_UNUSED_ARG(message);

    /* stop timer */
    tcpip_untimeout(pppoe_timeout, sc);
    PPPDEBUG((LOG_DEBUG, "pppoe: %c%c%"U 16_F ": session 0x%x terminated, %s\n", sc->sc_ethif->name[0], sc->sc_ethif->name[1], sc->sc_ethif->num, sc->sc_session, message));

    /* fix our state */
    sc->sc_state = PPPOE_STATE_INITIAL;

    /* notify upper layers */
    sc->sc_linkStatusCB(sc->sc_pd, 0);

    /* clean up softc */
    MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
    if (sc->sc_ac_cookie)
    {
        mem_free(sc->sc_ac_cookie);
        sc->sc_ac_cookie = NULL;
    }
    sc->sc_ac_cookie_len = 0;
    sc->sc_session = 0;
}

#endif /* PPPOE_SUPPORT */

